Getting an access token from Azure AD B2C using client's secret

access_token_azure_adb2c.go

/*
import (
 "encoding/json"
 "errors"
 "fmt"
 "io/ioutil"
 "net/http"
 "net/url"
 "strings"
)
*/

path := "https://login.microsoftonline.com/" + tenantID + "/oauth2/v2.0/token"
data := url.Values{}
data.Set("client_id", clientID)
data.Set("client_secret", secret)
data.Set("scope", "https://graph.microsoft.com/.default")
data.Set("grant_type", "client_credentials")

r, err := http.NewRequest(http.MethodGet, path, strings.NewReader(data.Encode()))
if err != nil {
  panic(err.Error())
}
r.Header.Add("Content-Type", "application/x-www-form-urlencoded")

resp, err := http.DefaultClient.Do(r)
if err != nil {
  panic(err)
}

defer resp.Body.Close()
responseBody, err := ioutil.ReadAll(resp.Body)
if err != nil {
  panic(err)
}

if resp.StatusCode != http.StatusOK {
  panic("status code: " + resp.Status + "; error details: " + string(responseBody))
}

var unmarshalled struct {
  Token string `json:"access_token"`
}
if err := json.Unmarshal(responseBody, &unmarshalled); err != nil {
  panic(err)
}

fmt.Println(unmarshalled.Token)